One example of a three-dimensional semiconductor device proposed in recent years is a semiconductor memory device having memory cells disposed three-dimensionally for increasing a degree of integration of memory (three-dimensional type semiconductor memory device).
In the above-described three-dimensional type semiconductor memory device, ends of conductive layers (word lines and so on) connected to gates of memory cells configure a stepped portion processed in a stepped shape. Moreover, contacts are formed on upper surfaces of the conductive layers in this stepped portion.
However, it sometimes occurs that the conductive layers and the contacts cannot be sufficiently connected due to variations in manufacturing processes, and there is a consequent risk that line resistance in the three-dimensional semiconductor device increases.